TALLAHASSEE – After more than four hours of deliberation Monday, Florida lawmakers are set to vote on a massive prison privatization plan for South Florida in what will likely be an emotionally fraught debate and a severe test of Senate President Mike Haridopolos' leadership.

The plan, a top priority of Haridopolos and Senate budget chief JD Alexander, would privatize more than two dozen prisons and work camps in South Florida. But though it has the clout of the legislative leaders behind it, the matter has split the Senate and could easily fail.

"If it goes down, it goes down," Haridopolos told reporters after the floor debate Monday. "But everyone recognizes if we fail on this vote that we'll have to find the savings elsewhere."

The move to privatize prisons in South Florida set off a flurry of lobbying opposition over the past few weeks from the Teamsters, which represents state correctional officers, and other public employee unions. But business groups like the Florida Chamber of Commerce have portrayed the plan as a sensible, business-like way for the state to save money.

Under the proposal, a private prison company would have to run the facilities for 7 percent – or $16.5 million annually – less than it costs the state Department of Corrections now.

Such savings, said Alexander, R-Lake Wales, "we can use reliably to fund issues in our budget that we say is important."

But the supposed gains of privatization have come under attack.

Two of the bill's leading critics, Sen. Mike Fasano, R-New Port Richey, and Sen. Paula Dockery, R-Lakeland, have questioned the numbers and said they simply don't add up.

Specifically, records obtained by Dockery's office from the Department of Corrections compare the daily cost per prisoner between private prisons and the most comparable public prison (a type of analysis the department itself uses internally, but has not released publicly. The results are mixed.

The privately run Bay Correctional Facility, for example, spent an average of $48.70 per prisoner daily in the 2010-11 fiscal year, compared to $43.78 at publicly run New River prison. Moreover, New River held "close management" prisoners who are more dangerous and thus more costly to confine, while private Bay prison didn't.

The largest of Florida's private prisons, Graceville, with 1,875 inmates last year, spent about $2 less per prisoner per day ($34.85) than its public-prison peer at Wakulla ($36.82), but 31 cents more per prisoner the year prior to that.

DOC spokeswoman Ann Howard said the public-private comparisons are imperfect, because no two prisons are exactly alike in population, health-care needs and security levels.

"When you compare the costs between institutions, adjustments need to be made, and a lot of them," Howard said. A prison with a higher percentage of "close management" prisoners may cost more because "those are some of the most expensive inmates we have."

Fasano and Dockery led efforts to kill the privatization bill Monday, with Fasano offering up language that would have gutted the plan and instead required the state to study the issue.

Fasano said that the Senate was "moving this thing forward too fast" and noted that nearly 4,000 correctional workers in South Florida could lost their jobs if private companies chose not to rehire them.

The proposal by Fasano to do a study instead went down narrowly by a 19-21 vote, which many thought forecast the final vote on the bill Tuesday. However, Sen. Dennis Jones, R-Seminole, who voted against Fasano's amendment, said he would cast a "no" in the final vote. He simply didn't see the need for a study to "prolong the inevitable," he said.

"Just kill the bill," he said.

Initially the Senate was slated to meet for 3 1/2 hours Tuesday morning. However, Haridopolos rescheduled the session for the afternoon, citing the need for more time for debate. The move also gives legislative leaders and other lobbying groups a few more hours to try to persuade lawmakers to switch their votes.

Haridopolos, R-Meritt Island, denied "twisting arms" himself.

"This is a very independent place," he said. "The old tradition that other people employed of twisting arms is not my style."

The House has a similar measure filed, but removed it from an agenda more than a week and a half ago when it appeared the Senate version was in trouble.